Gas turbine with fluid-driven auxiliary drive



GAS TURBINE WITH FLUID-DRIVEN AUXILIARY "DRIVE Filed Oct. 29, 1946 Sept. 30, 195 2 A. A. GRIFFITH v I 3 Sheets-Sheet 1 Sept. 30, 1952 .A. A. GRIFFITH 2,612,020

GAS TURBINE WITH FLUID-DRIVEN AUXILIARY DRIVE Filed Oct. 29, 1946; s Shets-Sheet 2 Sept. 30, .1952 A. A. GRIFFITH 2,612,020

was TURBINE WITH FLUID-DRIVEN Auxxumwk vs Filed om. 29, 1945 s Sheets-Sheet s Patented Sept. 30, 1952 UN'I'TED' ESTATES" 'GAS TURBINEWITH FDUIDeDRIV-EN n v AUXILIARY pawnv f r gain d Gem, Derby; Eng a a, assignortw .Rolls-BoyceLimited, Derb 'yg England; a British company InGreatiBritain Octob'er 4; 19451 ApplicationOctober 29, 1946,;Seria hNo. 706,449

This" invention concerns gas turbine power plants and has for its object toprovide means for'driving theauxiliary units. ofpthe power plant, the driving means being such as to enable the auxiliaries to be located subjstantially'where' clesired remotely from the pj'owenplant.

A further object of the present invention is to" provide a control for'the driving means: which is automatic and of a simple and therefore re'-' liable nature;

A further object of the present invention is to' speed which is independent ofthe operating conditions of the gasturbine power plant.

A specific embodiment ofthe present invenv tion will now be described, by way of example, with reference to the accompanying drawings whereof: V

Figure 1 is a diagrammatic representation of a gas turbine power'plant' for aircraft propulsion, and of driving means for the auxiliary units thereof in accordance with the present invention, and l Figures 2A and" 23 together constitute a side elevation, partly in section, oflth'e auxiliary'turbine and the drive from the latter to the auxiliaries for the gas'tur'bin'e power'plant.

Referrin to- Figure 1: the gas turbine power plant-comprises a turbine i a compressor 8. driven by the turbine through shaft I, a plurality of combustion chambers 8 through which the air from the compressor 6 passes to the turbine 5 and in which fuel is burnt to form the working medium of the power plant and a tail pipe 9 through which the exhaust gases from the turbine are discharged as a rearwardly directed jet by the action of which the aircraft is propelled forwardly.

Associated with the power plant is a group of auxiliary units which are required for its operation or the operation of the aircraft in which the plant is installed. These auxiliaries are for example a generator ID, a vacuum pump II, an oil pump I 2, a compressor l3 and a fuel pump M. The auxiliary units are all secured to the casing of a gear box I5. The gearbox I5 is driven by screams; (c1. ran-39.13)

the auxiliary turbine" f6 through thereduction gear generally indicated by the reference numeral II,v The drive fromjthe auxiliary-turbine I6 toea'ch of theauxiliaries' referred towill beset forth'in detailhereinafter; I A t g I f} The turbinelfiiis'. connected by' means of a pipe l8 with the compressor 6 and by means of pipeline I'S with another part of" the gas turbine power plant; for instance, the tail pipe 9; A-

butterfiy'valve' Mi-is disposed 'inpipe I8 and will regulate" the flow of air fromthe-compre'ssor B to the turbine I6 and thence through pipe I9- back to the gas turbine power plant 2 p Referringinow. to FigureZB: the auxiliary turbin'elficomprisesja casing'l'l whichfis connected with thepipe I8, arotor-"22- mountedwithin the casing, a shaft 23' which carries the rotor 22- bearings 24 carried by thecasingll and supporting the shaft 23, a diffuser 2-5' and a'conne'ctor 26 leading from the casing 2i to'the pipe I9.

Air travellingalong'thepipe l8 from: the com press or G-enters the easingm andis then "fed into the] rotor 22'- around the periphery thereof, passes therethrough along the connector 26 and so to the pipe I9. As a result the rotor 22 and its shaft23-arerotated".

The shaft 23 carries a pinion 21 which forms. one-member of a reduction gear train 28, 29,and 30. The'pinion 3I1-iscarrie'd by a shaft 3| which is supported in casine liby bearings 32. The

shaft 3i is the input shaft of the gear box IE and is connected through suitable gear trains with the-various auxiliary units. Thus, it is connected through bevel gears 33 and ,34 with the generator I0, through bevel gears 35, 36 with the compressor I3, through gears31, 38 with layshaft 39 and thence throughbevels 40 and-AH with the fuel pump I4 and through bevels 48; .4! and 42 with the oil pump l2; An extension ofthe shaft 39" leads to thevacuumpump H Whilst an extensi'on of the'shaft 3i ils'coupled toa constant speed unit generally indicated by the reference numeral 43.

The constant speed unit 43 is of known con-' I Pressure fluid exspeed unit is adjusted to a predetermined datum speed which whilst it is maintained results in the valve remaining closed. In the event that the speedof shaft 3| departs from the datum value, the governor will actuate its valve and as a consequencewill permit pressure fluid from pipe 55 to pass by one or other of pipes 46 to the motor 54. The ram of the latter is connected by linkage d8, 49 with the butterfly valve 25).

With the control described, upon a departure of speed from the datum value the valve 20; will be adjusted to reestablish this value. This control is provided since it is considered desirable that the auxiliary units be driven at a substantially constant speed which is independent of the Operating conditions of the gas turbinepower plant. This is particularly desirable when generators and compressors for pressurizing comauxiliary air-driven turbine. for driving said accessory means, a fluid connecting duct between said air compressor and said air-driven turbine for conveying compressed air to drive the latter. valve means in said fluid connecting duct, means for actuating said valve means for controlling the speed of said air driven turbine to be independent of the speed of said gas turbine, and a fluid exhaust duct between said air-driven turbine and a space where the pressure is substantially less than thatexisting in said combustion-apparatus.

3. A gas-turbine power plant as claimed in claim 2, wherein said means for actuating the valve means comprises a speed responsive device connected to be driven by said air turbine including a control valve, a hydraulic motor controlled by said control valve and connecting means bepartments of the aircraft are provided."

description has been made with reference to an auxiliary turbine 13 of theradial-flow type, other types of turbine may be used instead;

When starting a gas turbine power plant such as that shown diagrammatically in Figure 1 it is customary to bleed ofi a proportion of the air de-.

livered by the compressor 6 in ordertoobtain a temporary enrichment of the fuel-air mixture entering the combustion chambers 8. The advantages associated-with the driving. means. for

the auxiliary units described above is that such enrichment mayv be effectedand regulatedby the air passing to the au c iliaryf'turbine i5."

I claim; I v

1. A gae-turbine, power plant comprising in combination an air compressor, combustiom apparatus, connected to be supplied directly from said air compressor, a gas-turbine connected to be supplied from said combustion-apparatus coupledto. drive said air compressor,newer-plant accessory means including at least ajfuel pump supplying said combustion apparatus, an auxiliary air-driven turbine for driving said power plant accessory means, a fluid connecting duct between said air compressor, and said air driven turbine for conveying compressed air to drive the latter, and a fluid exhaust duct between saidairdriven turbine and a space where the pressure is substantially less than that existing in said combustion-apparatus. I

2. A gas-turbine power plant comprising in combination an air compressor, combustione apparatus connected to-be supplied directly from said air compressor, a gas-turbine connected to be supplied from said combustion-apparatus coupled to said air compressor to drive it, powerplant accessory means includingat least a fuel pump supplying said combustion apparatus, an

tween said hydraulic motor and said valve in said fluid duct for controlling the fluid intake to said air-driven turbine from said air compressor.

.4. A gas-turbine power plant comprising in combination an air compressor, combustionapparatus supplied thereby, a gas-turbine connected to be supplied from said combustionapparatus and coupled to said air compressor to drive it, power plant accessory meansincluding at least a fuel pump supplying said combustion apparatus, an auxiliary air-driven turbine for driving said power plant accessory means, a fluid connecting duct between said air compressor and said air-driven turbine for conveying compressed air to drive the latter, speed responsive means responsive to the speed of said air-driven turbine, means actuated by said speed responsive means for controlling the speed of the air-driven turbine to be independent of the speed of saidgas turbine, and a fluid exhaust duct between said air-driven turbine and a space where the pressure is substantially less than that existing in said combustion-apparatus.

5. A power plant as claimed in claim 4 further comprising a throttle valve in said duct actuated by said speed responsive means. l

ALAN ARNOLD GRIFFITH.

REFERENCES creep ihe following references are of record in the file of this patent:

, UNITED STATES PATENTS 

